> On Feb 22, 2019, at 12:14 PM, Steve Wise <swise@xxxxxxxxxxxxxxxxxxxxx> wrote:
>
>
> On 2/22/2019 10:36 AM, Jason Gunthorpe wrote:
>> On Sun, Feb 17, 2019 at 06:09:09PM +0100, Håkon Bugge wrote:
>>> During certain workloads, the default CM response timeout is too
>>> short, leading to excessive retries. Hence, make it configurable
>>> through sysctl. While at it, also make number of CM retries
>>> configurable.
>>>
>>> The defaults are not changed.
>>>
>>> Signed-off-by: Håkon Bugge <haakon.bugge@xxxxxxxxxx>
>>> drivers/infiniband/core/cma.c | 51 ++++++++++++++++++++++++++++++-----
>>> 1 file changed, 44 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
>>> index c43512752b8a..ce99e1cd1029 100644
>>> +++ b/drivers/infiniband/core/cma.c
>>> @@ -43,6 +43,7 @@
>>> #include <linux/inetdevice.h>
>>> #include <linux/slab.h>
>>> #include <linux/module.h>
>>> +#include <linux/sysctl.h>
>>> #include <net/route.h>
>>>
>>> #include <net/net_namespace.h>
>>> @@ -68,13 +69,46 @@ MODULE_AUTHOR("Sean Hefty");
>>> MODULE_DESCRIPTION("Generic RDMA CM Agent");
>>> MODULE_LICENSE("Dual BSD/GPL");
>>>
>>> -#define CMA_CM_RESPONSE_TIMEOUT 20
>>> #define CMA_QUERY_CLASSPORT_INFO_TIMEOUT 3000
>>> -#define CMA_MAX_CM_RETRIES 15
>>> #define CMA_CM_MRA_SETTING (IB_CM_MRA_FLAG_DELAY | 24)
>>> #define CMA_IBOE_PACKET_LIFETIME 18
>>> #define CMA_PREFERRED_ROCE_GID_TYPE IB_GID_TYPE_ROCE_UDP_ENCAP
>>>
>>> +#define CMA_DFLT_CM_RESPONSE_TIMEOUT 20
>>> +static int cma_cm_response_timeout = CMA_DFLT_CM_RESPONSE_TIMEOUT;
>>> +static int cma_cm_response_timeout_min = 8;
>>> +static int cma_cm_response_timeout_max = 31;
>>> +#undef CMA_DFLT_CM_RESPONSE_TIMEOUT
>>> +
>>> +#define CMA_DFLT_MAX_CM_RETRIES 15
>>> +static int cma_max_cm_retries = CMA_DFLT_MAX_CM_RETRIES;
>>> +static int cma_max_cm_retries_min = 1;
>>> +static int cma_max_cm_retries_max = 100;
>>> +#undef CMA_DFLT_MAX_CM_RETRIES
>>> +
>>> +static struct ctl_table_header *cma_ctl_table_hdr;
>>> +static struct ctl_table cma_ctl_table[] = {
>>> + {
>>> + .procname = "cma_cm_response_timeout",
>>> + .data = &cma_cm_response_timeout,
>>> + .maxlen = sizeof(cma_cm_response_timeout),
>>> + .mode = 0644,
>>> + .proc_handler = proc_dointvec_minmax,
>>> + .extra1 = &cma_cm_response_timeout_min,
>>> + .extra2 = &cma_cm_response_timeout_max,
>>> + },
>>> + {
>>> + .procname = "cma_max_cm_retries",
>>> + .data = &cma_max_cm_retries,
>>> + .maxlen = sizeof(cma_max_cm_retries),
>>> + .mode = 0644,
>>> + .proc_handler = proc_dointvec_minmax,
>>> + .extra1 = &cma_max_cm_retries_min,
>>> + .extra2 = &cma_max_cm_retries_max,
>>> + },
>>> + { }
>>> +};
>> Is sysctl the right approach here? Should it be rdma tool instead?
>>
>> Jason
>
> There are other rdma sysctls currently: net.rdma_ucm.max_backlog and
> net.iw_cm.default_backlog. The core network stack seems to use sysctl
> and not ip tool to set basically globals.
>
> To use rdma tool, we'd have to have some concept of a "module" object, I
> guess. IE there's dev, link, and resource rdma tool objects currently.
> But these cma timeout settings are really not per dev, link, nor a
> resource. Maybe we have just a "core" object: rdma core set
> cma_max_cm_retries min 8 max 30.
I don’t know, I think you make a fairly good argument for leaving it as a sysctl. We have infrastructure in place for admins to set persistent sysctl settings. The per device/link settings need something different because link names and such can change. Since these are globals, I’d leave them where they are.
--
Doug Ledford <dledford@xxxxxxxxxx>
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